日本於一九九四年三月完成了選舉制度改革，將中選舉區制改為小選舉區比例代表並立制。本文主要探討兩個主題。第一個是，九○年代以前，自民國黨曾兩度嘗試將中選舉區制改為小選舉區制，但是均失敗。又為何自民黨下臺不到一年，卻完成了以小選舉區制為中心的選舉制度改革？既有的反對勢力，尤其是當時的在野在黨為何在成為執政黨之後，反而成立了對自嚴黨有利的選舉級度呢？第二主題是，在日本實施四十六年之久的中選舉區制，為何在九○年代被認為有弊端呢？為何直接被替換？新選舉制度是否達到改革的目的？ 日本的經驗顯示，期望經由選舉制度的改革來達成政治問題的解決，似乎太過樂觀。

　　　　　Japan completed the electoral reform of the House of Representatives in 1994 which changed the electoral system, from SNTV (multi-member district with single non-transferable vote system) to the mixed system of single-member and proportional-representation districts. This paper studies two themes. First, why did the reform of the electoral system conducted by the LDP (Liberal-Democratic Party) twice before the 1990's, fail while this one within one year after the LDP cabinet had resigned? Succeed. And why did the opposition party, after becoming the ruling power in 1994, approve of the electoral reform which was advantageous to the LDP? Second, why was not SNTV, which and been executed for 46 years, found with flaws till the 1990's? why was SNTV directly substituted? Did the new electoral system accomplish the main of reform? According to this analysis, the attempts to solve Japan's political problem through electoral reform are not likely to succeed.